The annual maximum series of flood magnitude in a river has a normal distribution with a mean of 6000 m^3/s and a standard deviation of 800 m^3/s
A. What is the probability in each year that a flood magnitude would exceed 5000 m^3/s
B. if a channel is built to control the 20 year flood, what is the probability that the channel will be over topped in any 4 year period
C. What is the probability that the channel will be over topped twice in and 4 year period
D. If the channel is overtopped for 2 years in a row, renovation cost will increase too much. What is the probability that the channel will be overtopped for only 2 years in a row in a 4 year period